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- R L. WALKER. ,STEAM BOILERFIRE BOX.

Patented Feb. 12, 1884.

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UNITED STATES ATENT OFFICE,

RoRERr L. WALKER, on BOSTON, iunssnonusn'rrs, Assm oR To THE WALKER sMoKELnss FURNACE COMPANY, or SAME PLACE.

STEAM-BOILER FIRE- Box.

SPECIFICATION forming part of Letters Patent No. 293,544, dated February 12, 1884. Y Application filed May 23, 1883. (No model.)

' of Boston, in the county of Suffolk and State of Massachusetts, haveinvented certain new and useful Improvements in Steam-Boiler Fire-Boxes, of which the following is a specification.

This invention relates to improvements in the firebox or furnace for which I obtained Letters Patent No. 260,810, dated July 11, 1882, in which the fire-box or furnace is divided by a longitudinal water'leg into two compartments having corrugated fire-brick roofs and openings covered alternately bya damper, so that the smoke from the covered compartment must pass into the uncovered compartment.

The objects of my present invention are to simplify the construction of the waterleg, to

improve the construction of the damper, to.

render certain and effective the water-circulation through the damper, to decrease the frietion incident to moving the damper, to provide means for counterbalancing the damper, and to provide facilities for enabling the engineer or fireman to operate the damper by means of steam or compressed air.

In the accompanying drawings,which illustrate so much of a locomotive fire-box as is deemed necessary to show all my improvements, as embodied in the best way now known to me, Figure 1 is a central longitudinal section;

Fig. 2, a front elevation and Fig. 3 is a 1on gitudinal section through the doorway. A. is thelongitudinal water-leg, centrally located in the fire-box, to form two compartments, partly covered by corrugated fire-brick a. "In my patent above mentioned this water-leg extended the whole length of the firebox, and communication between the compartments was made by an'opening through the water-leg. This opening, as is well known to boiler-makers, was difficult and expensive to make 5 and one part of my present invention consists in a longitudinal water-leg centrally located in the fire-box or furnace of a steam-boiler shorter than the fire-box, and having the space between its end and the tubesheet covered with a refractory material. The space a, between the end of the water-leg A and the tubesheet 13, forms the communication between the two compartments of the. fire-box, and is covered with corrugated fire-brick a. The water-circulation through the leg A is effected by inclined pipes 0?, which pipes also serve as supports for the damper D.

Another part of my present invention consists in simple and novel construction of the damper.

The damper D is formed of a series of tubes, (1, connecting by pairs, upper water-blocks or return-bends, d, to ahollow shaft, d, divided into water spaces by diaphragms (2. One tube of the pair leading from each waterblock d communicates with water-spaces on opposite. sides of one of the diaphragms (1 thereby forming a channel, through which the water must flow from the hollow shaft to a water-block through one tube, and back from the water-block to the shaft through the other tube. The spaces d between the tubes is filled with two pieces of plate-iron or thelike riveted together. The tubes (Z are provided with right and left hand screw threads, by means of which they are secured to the hollow shaft d and the return-bends cl. The hollow shaft is thus made separate from the rest of the damper, and can be readily finished in an ordinary lathe, instead of requiring a lathe 'of great swing, as when the damper is all in one piece.

To insure a certain and effective water-cir- The hollow shaft d" per, whereby the hottest and coolest water are connected to facilitate circulation, forms another feature of my present invention. The

inner end of the damper-shaft is turned to fit water -tight in the bearing-block. (P, and is held in close contact therewith by means of a spring, d bearing against a collar, d-f, on the damper-shaft, and having its thrust received by a plate, 0. To decrease the friction of this plate 0, incident to turning the damper, I have interposed between it and the plate 0, adjustable on the bolts 0 by means of the nuts 0, for regulating the tension of the spring (i a series of conical rollers, 0 By means of this feature of my present invention the friction is reduced to the minimum. To further facilitate the movements of the damper, and to prevent its sudden fall or slamming, when operated by a lever arranged to give the requisite movement without being thrown all the way over, the lever F is mounted to move freely on the outer end of the damper-shaft (Z and is provided with a finger-lever, f,.

spring f and stop f'. The stop f engages with slots in a quadrant or disk, f secured to the damper-shaft d", and by means of the finger-lever and spring can, be shifted from one slot to another, to move the damper,without moving coincidently with the damper. The slots are preferably arranged so that the the first movement of the lever F brings the damper to a vertical position, when the lever F is moved back to bring the stop f to another notch, and its second movement brings the damper in position to cover the opening of one compartment. \Vhile shifting the lever F the damper is leftin a vertical position, and would be liable to fall. To prevent the damper falling in such cases, another feature of my invention consists in a spring, G, adapted to resist the movement of the damper to either side from the vertical.

Ihave shown coiled spring, G, located beneath the foot-board, bearing at one end 011 a fixed plate, g, and at its other end on a plate, 9, attached to a rod, ft-extending through the spring, and connected, by means of a chain, passing over pulleys g, to preserve its proper direction, to an arm, 9 secured to the damper-shaft d in such a manner that when the damper is vertical the spring will be extended to its limit, and a movement of the damper in either direction will compress the spring and be correspondingly resisted.

It has been found in practice that operating the damper by means of a lever, whether with one or two movements, is more or less inconvenient, and not always reliable; and therefore another feature of my present invention is to adapt the damper to be operated by steam or air. This I accomplish by means of a cylinder, I-I, supplied from the boiler by the pipe h, or from the compressed-air holder. A handle, h, for operating valves for controlling the steam or air, is accessible to the fireman or engineer, or both. The piston-rod h is connected to an arm, If, secured to the dampershaft d. In this arrangement, by proper manipulation of the handle h, as will be obvious to all familiar with steam-engines, the damper can be readily operated and controlled by steam, the lever being removed. A socket is, in this instance, secured to the damper-shaft into which the lever is inserted to move the damper while getting up steam.

As two doors are required in my improved -boX,-of-a water-leg centrally located therein and dividing it-into two compartments, a space between the water-leg and tube-sheet forming a communication between the two compartments, and corrugated fire-brick covering this space and partly covering the compartments, substantially as set forth.

. 2. 'A damper for covering the openings from the compartments of a firebox, substantially as hereinbefore described, consisting of a series of pipes connecting return-bends or waterblocks .to water-spaces in the damper-shaft, as

and for the purposes set forth.

3. The combination, substantially as hereinbefore set forth, of a damper for covering the openings from the compartments of afireboX, and having a water-channel, substantially as described, within it, with a pipe connecting the inner end of the damper-shaft with thespace over the crown-sheet, and a pipe connecting the outer end of the damper-shaft with the rear water-leg, as and for the purpose set forth.

4. The combination, substantially as here inbefore set forth, of a damper, a spring for maintaining a close fit between one end of the damper-shaft and its bearing, and a thrust plate for supporting one end of the spring, with a series of anti friction rollers, located substantially as described, and for the purposes set forth.

5. The combination of a damper for cover- IIO ing two openings and a lever for o perating valve operated by hand, by means of which steam or air may be admitted to and released from the cylinder, to move the piston in either direction, for the purpose set forth.

- ROBERT L. WALKER.

Witnesses:

LAURITZ N. MoLLnR, JonN R. Snow. 

